I too had a problem with getting Pandas in this scenario. If you start it over, be sure to save it just before you have evertyhing completed to get the Pandas.
This scenario only allows you to get the Pandas once. Once you have bought a pair (with the game time running) you can't get any more! I don't know whether if you don't get them right away, they disappear or not. But if you pause the game you can buy as many as you like.
The second time I played the game I saved up enough cash to build 4 Panda exhibits (and no money cheat!). 3 of the 4 pairs bred. I use both Bamboo & Himalayan Pines.
PS Pugseli - you can often find info on animals in the Startegies section. I didn't see anything on Asian elephants - here's the basics:60 RainForest, 20 Grass, 20 FreshWater, 12 squares FULL of foliage (use a minimum of 10 Foxtail Palms. the rest can be FT Palm, RF Fern, or Giant Ficus). 4 small rocks, 1 large rock, 1 elephant shelter. Gets you 100.